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Question
What proof of the big bang theory is there? Also what is dark matter and how was it discovered?

Answer
HI Haleigh,

There are lots of different data that suggest the Universe started with the Big Bang.  The best and most direct evidence is the expansion of the Universe,  This was first discovered by Hubble, and the expansion rate of the Universe, as measured by distance galaxies, is called Hubble's Law, which provides clear evidence of an expanding Universe due to the Big Bang.  

There are other pieces of evidence, such as the cosmic microwave background.  Very early, the Universe was really hot. However, as it expanded, it cooled, and some of the energy was leftover which formed a glow in microwave wavelengths, both predicted by the Big Bang Theory.

There is also the abundance of the elements, both in how much of each they existed billions of years ago and today.  There is also the formation and distribution of galaxies, in that they are not distributed evenly around the Universe, but formed in clumps, as predicted by the Cosmic Microwave Background and the Big Bang Theory.  

Dark matter is some sort of mass that makes up most of the mass of galaxies.  This causes galaxies to spin faster than predicted with standard physics and mass, which was how dark matter was originally discovered.  The leading theory is a WIMP, a Weakly Interactive Massive Particle - a subatomic particle that doesn't interact with light but is very heavy.  Experiments such as the Large Hadron Collider (LHC) at CERN in Switzerland are trying to find it, but as of now, we do not know what it is.

Peace,
Brad

Astronomy

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Brad Tucker

Expertise

I'm happy to answer any general questions about Astronomy, Astrophysics, and Cosmology. I'm also happy to take general, specific, and detailed questions related to supernovae, Baryonic Acoustic Oscillations, the Cosmic Microwave Background, dark matter, dark energy, and the Big Bang Theory. I'm also happy to chat about Astronomy/Astrophysics education and careers, and philosophy and science.

Experience

I am a professional research astronomer/astrophysicist/cosmologist. My research focuses on studying supernovae and using them to measure the properties of the Universe, such as how fast it is growing and what it is made of. I also frequently give talks to school groups and the public, and am a regular guest on various radio stations.

Organizations
Current Research Fellow at Mt. Stromlo Observatory, the Australian National University, and in the Department of Astronomy, University of California, Berkeley.

Publications
Lots of journals, including the Astrophysical Journal, the Astronomical Journal, and Nature. I am currently in the middle of writing my first popular book.

Education/Credentials
B.A. Philosophy, University of Notre Dame, Notre Dame, IN USA B.A. Theology, University of Notre Dame, Notre Dame, IN USA B.Sc. Physics, University of Notre Dame, Notre Dame, IN USA Ph.D. Astrophysics, Mt. Stromlo Observatory, the Australian National University, Canberra, ACT, Australia

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